Slight Engine Miss

[SILVER2000SVT]

I have a slight engine miss. It's been there at an idle for as long as I can remember. But I also if I raise the RPM up to around 2500 it's more noticeable.

THis might be related...Was at the track a couple of weeks ago, after making a run I went back to the stagging lanes and the slight miss was now a dead miss. I rev it up a little and it goes away and runs like normal.

The TR6's aren't that old, and they've always looked good when I have replaced them and I gap them at .036.

It's not the fuel filter, I stay on top of that, and I have fuel pressue gauge that would tell me if that were ever a problem.

I'm thinking I may have a coil pack getting weak, but how do you check for this because it's not really a dead miss, just slight.

Maybe the fuel injectors are getting dirty. What's the best way to clean these. Can you take them somewhere and have them professionally cleaned? I figure this would be good to do for preventative purposes even if it weren't the problem.

Maybe a failing fuel injector. How do you check for this?

Other ideas to look for?

[Silver_2000]

I bet its your plugs - when is last time you looked at them ?

Do you have a "race " program ? When is last time you ran it ?
Are you still running "Warm" program ?

These things can alter plugs...

[SILVER2000SVT]

I bet its your plugs - when is last time you looked at them ?

Do you have a "race " program ? When is last time you ran it ?
Are you still running "Warm" program ?

These things can alter plugs...


Good point.

The plugs have about 2K-3K miles on them. I've pretty much ran the same setup for a while now and have changed the plugs about every 10K miles and they look good every time. They aren't really expensive so it couldn't hurt to try another set and do an inspection.

I've never run a race program, I have an all weather tune also. It uses a locked timing table to where the computer doesn't add any additional timing in the cooler air temps. So I shouldn't have any significant factors there.

[99WhiteBeast]

I've been fighting something similar off and on for about six months although mine seems to be more related to the EGR system. Mine truck will stumble off idle under partial (light) throttle and then again at around 2500 rpm.
I get various codes that will clear themselves at times (P0401 insufficent flow and PO402 excessive flow). I've replaced all the EGR pieces (valve, solenoid, vacuum module) and it seemed to clear it up for a while.

It recently came back and through the insufficent flow code again. I put a bottle of gasoline additive (Amsoil Perfomance Improver) designed to clean injectors and EGR system and it has worked so far.

I beleive mine may be related to carbon build up over time from a rich tune. I have lots of timing (19/21) in both my programs but also a lot of fuel (11.75-12.1 A.F)

[SILVER2000SVT]

I've been fighting something similar off and on for about six months although mine seems to be more related to the EGR system. Mine truck will stumble off idle under partial (light) throttle and then again at around 2500 rpm.
I get various codes that will clear themselves at times (P0401 insufficent flow and PO402 excessive flow). I've replaced all the EGR pieces (valve, solenoid, vacuum module) and it seemed to clear it up for a while.

It recently came back and through the insufficent flow code again. I put a bottle of gasoline additive (Amsoil Perfomance Improver) designed to clean injectors and EGR system and it has worked so far.

I beleive mine may be related to carbon build up over time from a rich tune. I have lots of timing (19/21) in both my programs but also a lot of fuel (11.75-12.1 A.F)

I've had one of those EGR codes a year and a half ago and it cleared itself, and nothing since. I'm not throwing any other codes either. The only other thing it does that's weird is ever since I got my exhaust and Throttle body installed 2 years ago it wants to die under a cracked throttle (like 2%) when it's cold and I've just pulled out of the driveway and it doesn't do it any more after the first 2 minutes. I thought it was the throttle body and put the stock one back on a few weeks ago, but that wasn't it. Two years ago JDM told me this was normal and I really haven't worried about it since. But this could be related maybe?

[99WhiteBeast]

Have you tried cleaning up the IAC?

[SILVER2000SVT]

Have you tried cleaning up the IAC?

Yes, not too long ago I cleaned it.